WASHINGTON -- Stiffening their sinews and summoning up their blood, pugnacious liberals and conservatives who relish contemporary Washington's recurring Armageddons are eager for a summer-long struggle over Barack Obama's nominee to replace Supreme Court Justice John Paul Stevens. They should pause and ponder how recently and radically the confirmation process has changed.

By 1939, the Supreme Court had been embroiled in political controversy for half a decade. It had declared unconstitutional some important New Deal policies, and FDR had reciprocated by attempting to "pack" the court by enlarging it, which had earned him a rebuke in the 1938 elections. Yet when on Jan. 5, 1939, he nominated Felix Frankfurter to fill a court vacancy, the Harvard law professor sailed through Senate hearings and the confirmation vote in 12 days. It was a voice vote, with no audible dissent.

On March 20, FDR nominated William O. Douglas to fill another vacancy. Although the 40-year-old Douglas had no judicial experience -- he was chairman of the Securities and Exchange Commission -- and would be the youngest justice in more than a century, he was confirmed 15 days later. No witness testified against him.

Linda Greenhouse of The New York Times notes that when Stevens was nominated in 1975 to fill the first vacancy since the 1973 Roe v. Wade decision, he was asked no question about abortion during his confirmation hearing. He was confirmed 98-0, as was Antonin Scalia in 1986. Things changed the next year, when Ted Kennedy used a demagogic Senate speech to launch a successful liberal crusade against Robert Bork.

As Stevens departs, the eight remaining justices are all products of the Harvard, Yale or Columbia law schools; all are former federal judges. Professor Terri L. Peretti, a Santa Clara University political scientist, notes (in Judicature, Nov.-Dec. 2007) that the court has often included judges with political experience.

The greatest justice, John Marshall, who made the court a nation-shaping force, had been a state legislator and congressman. Between 1789 and 1952, most justices had some legislative or executive political experience. Chief Justice William Howard Taft, a former president, was followed by Charles Evans Hughes, a former New York governor. Hugo Black had been a senator from Alabama. Earl Warren had been California's governor, which became a problem: Because President Eisenhower, like many others, believed that political thinking sometimes supplanted jurisprudential reasoning in Warren's decision-making, he sought judicial experience in his remaining four nominees.

In 1971, Richard Nixon nominated the last two justices without such experience, William Rehnquist and Lewis Powell. The last justice with experience in elective politics was Sandra Day O'Connor, who had been an Arizona state legislator before becoming a judge. Bill Clinton seriously considered four prominent politicians for Supreme Court nominations -- New York Gov. Mario Cuomo, Secretary of Education and former South Carolina Gov. Richard Riley, Secretary of the Interior and former Arizona Gov. Bruce Babbitt and Senate Majority Leader George Mitchell.

Peretti believes that when, with the 1954 Brown decision, the court began the dismantling of segregation, Warren's political skills were apparent in the unanimity of the decision as well as the fact that it was "short and non-legalistic" and was "a public appeal" accessible to a broad public rather than "a cogent legal argument whose reasoning lawyers and academics would admire." But although the court played a crucial role in overturning the South's social structure, the need for such a dramatic judicial role is rare and there is no visible occasion for it today, so there is slight need to select politically experienced justices.

Conservatives spoiling for a fight should watch their language. The recent decision most dismaying to them was Kelo (2005), wherein the court upheld the constitutionality of a city government using its eminent domain power to seize property for the spurious "public use" of transferring it to wealthier interests who will pay higher taxes to the seizing government. Conservatives wish the court had been less deferential to elected local governments. (Stevens later expressed regret for his part in the Kelo ruling.)

The recent decision most pleasing to conservatives was this year's Citizens United, wherein the court overturned part of the McCain-Feingold campaign finance law. The four liberal justices deplored the conservatives' refusal to defer to Congress' expertise in regulating political speech.

So conservatives should rethink their rhetoric about "judicial activism." The proper question is: Will the nominee be actively enough engaged in protecting liberty from depredations perpetrated by popular sovereignty?